William T. Pettigrew

Potassium influences on yield and quality production for maize, wheat, soybean and cotton

Potassium is one of the principle plant nutrients underpinning crop yield production and quality determination. While involved in many physiological processes, potassiums impact on water relations, photosynthesis, assimilate transport and enzyme activation can have direct consequences on crop productivity. Potassium deficiency can lead to a reduction in both the number of leaves produced and the size of individual leaves. Coupling this reduced amount of photosynthetic source material with a reduction in the photosynthetic rate per unit leaf area, and the result is an overall reduction in the amount of photosynthetic assimilates available for growth. The production of less photosynthetic assimilates and reduced assimilate transport out of the leaves to the developing fruit greatly contributes to the negative consequences that deficiencies of potassium have on yield and quality production. Goals aimed toward increasing crop productivity and improved quality dictate either increased potassium supply or more efficient use of potassium. Developing plants that more efficiently use potassium might be a worthwhile goal for geneticists.

Dry matter production, nutrient uptake, and growth of cotton as affected by potassium fertilization

Abstract Insufficient potassium (K) nutrition produces detrimental effects on cotton (Gossypium hirsutum L.) lint yield and fiber quality. To further understand the deleterious effects caused by K deficiency, a 2‐yr (1991 and 1992) field study was conducted to determine how dry matter partitioning and nutrient concentrations of various plant tissues for the cotton genotypes, ‘DES 119’ and ‘MD 51 ne’, were altered by varying the application rate of fertilizer K and nitrogen (N). All plots received a preplant application of 112 kg N ha‐1, and half of the plots were later sidedressed with an additional 38 kg N ha‐1. Within each N treatment, half the plots received 112 kg K ha‐1, preplant incorporated, with the remaining plots not receiving any fertilizer K. Dry matter harvests were taken three times in 1991 and two times in 1992. At cutout (slowing of vegetative growth and flowering), plants that received K fertilization had a 14% more leaf area index (LAI), a 3% increase in the number of main stem nodes, an...

Corn Yields Benefit in Rotations with Cotton

Continuous cotton (Gossypium hirsutum L.) was the primary crop for the Mississippi Delta until recently. Corn (Zea mays L.) is now grown on about 1 million acres in Arkansas, Mississippi, and Louisiana, usually in rotation with cotton. This research evaluated corn’s performance in a four-year furrow irrigated rotation with cotton at Stoneville, MS. The experimental design was a randomized complete block with a split-plot arrangement of treatments replicated eight times. Whole plots were cropping sequences assigned at random. Cropping sequences were continuous cotton, continuous corn, corn-cotton-corn-cotton, or cotton-corncorn-cotton. Four adapted corn hybrids and cotton cultivars were grown as subplots beginning in 2000 to 2003. Corn grain yields were greater following cotton than continous corn in 2001 (169 bu/acre vs. 160 bu/acre) and 2002 (126 bu/acre vs. 117 bu/acre). Grain yields from continuous corn differed among years but with no consistency. Hybrids differed in yield among all years but no consistency in these data was noted. Test weights for continuous corn differed among years but were not below the requirement for US No. 2 yellow corn. Weights of 100 kernels did not differ among years or treatments. Economics dictate cropping sequences but corn can benefit from following cotton in rotation.